At least eight people have locked themselves to railway tracks in Dunedin protesting against a train which transports coal.
A trio of environmental groups are opposing the daily coal train that runs from Southland's Bathurst Resources' Takitimu mine to a Fonterra milk factory in Temuka, to the north.
Coal Action Network Aotearoa spokesperson Fiona Clements says Fonterra buys coal to dry milk powder for export.
"Fonterra is driving the demand for further coal expansion, desecrating the whenua... My whakapapa is on the line, being carted off like carbonised bones, no longer of flesh but stone.
"This happens on a daily basis past my own home transporting the world’s dirtiest fossil fuel. This undermines Mana whenua and our place here as kaitiaki of Papatūānuku”.
Other advocates are waving flags and banners at Dunedin's railway station.
The group claims the train "makes a mockery of what our city is trying to achieve", noting Dunedin last year declared a climate emergency.
In a statement, Fonterra told Newshub it was "committed to reducing its carbon footprint and transitioning to renewable energy".
"We have a target of net zero emissions at our manufacturing sites by 2050. We have already announced our commitment not to install any new boilers or increase capacity to burn coal. We have started transitioning our manufacturing sites to renewable energy sources, the most recent being our Te Awamutu site which is now powered by wood biomass."
Coal Action Network Aotearoa doubted this, claiming Fonterra is the only reason the Takitimu mine is still open.
This week the Government also declared a climate emergency.
Former Green MP and current chief executive of Forest & Bird, Kevin Hague, expressed support for the protesters on Twitter.
"I strongly support the @coalaction people blocking the coal train in Dunedin. We no longer have the time to make transition gradual. If we know how to decarbonise something (like milk drying) there's no excuse for not doing it now."
